The present invention relates to the testing of bare integrated circuits through wirebonding and, more specifically, to breaking the wirebonds after testing.
Integrated circuit technology has progressed so that it is possible to mount a bare integrated circuit directly to a circuit board without enclosing it in a package having solder pins for mounting. One method of mounting a bare integrated circuit is called flip chip, which is commonly known in the art.
In using the flip chip technique, the integrated circuit is tested before installation on the circuit board. One method for testing flip chips is by wirebonding to the individual bond pads of the integrated circuits and exchanging signals between a test apparatus and the integrated circuit. One problem with testing a bare integrated circuit using wirebonding is that the wirebonds must be removed from the bond pads without damaging the integrated circuit.
One known method for removing wirebonds uses a high pressure air pulse directed at the wirebonds to break the wirebonds and remove them from the integrated circuit. This technique results in wirebonds that are broken unevenly with varying amounts of wirebond connected to the bond pads of the integrated circuit. When the integrated circuits are attached to a circuit board, the uneven wirebonds may cause electrical continuity problems at the solder joint joining the bond pad to the circuit board traces. Continuity problems occur since the uneven leads may cause the integrated circuit not to lay flat on the circuit board traces.
It would therefore be desirable to provide a method and apparatus of removing the wirebonds from an integrated circuit uniformly so that the integrated circuit can be reliably attached to a circuit board for its intended application.